Cern Week 9

So Monday was spent converting LeTex to wiki and doing some final stress test and such on my server. Further I checked the failover mechanism. Which seams to work fine. Quite simple in OpenLdap to sync servers. The next day I started benchmarking client performance. Which seams to be totaly ok. This is a little test where lxb5477 authentikates over Ldap and lxb5478 uses /etc/passwd.

bash-3.00$ time ssh lxb5477 "/bin/true"

real    0m0.388s
user    0m0.013s
sys     0m0.010s
bash-3.00$ time ssh lxb5478 "/bin/true"

real    0m0.373s
user    0m0.009s
sys     0m0.014s

This is quite a nice result. Further I investigated in using a caching mechanism on the client so that not every

ls

has to do an ldap query. I tested some tools and sort of stuck with nscd (name service cache daemon) which improved performace hugely.

[root@lxb5477 ~]# /etc/init.d/nscd stop
Stopping nscd:                                            [  OK ]
$ time for i in `seq 100`; do ls ; done
real    0m1.684s
user    0m0.253s
sys     0m0.453s

[root@lxb5477 ~]# /etc/init.d/nscd start
Starting nscd:                                            [  OK ]
$ time for i in `seq 100`; do ls ; done
real    0m0.393s
user    0m0.099s
sys     0m0.254s

So I did some research on this an configured it to fit with owr cluster system.

I registred for an intel training on multi core programming which Cern is paying for me. And the good thing is that I get a fancy Certificate everyone wants nowerdays.
From : http://openlab-mu-internal.web.cern.ch
A Multi-threading and Parallelism Workshop will be held on the 4^th and 5^th of October at CERN. Experts from Intel will lead the two day event and help you improve your knowledge by explaining the key intricacies of parallel programming and presenting the most efficient solutions to popular multi-threading problems. A hands-on lab is also planned where participants will be able to improve their understanding of multi-threaded programming methodologies and learn to use tools for debugging and profiling multi-threaded applications.
So to prepare for this I started to hack up some pthreaded programs. What was quite fun. I wrote a little clone of GNU seq to use both cores of my 2 core machine. This was basically a tradeoff from memory to speed. Bacause I cach the results of one core in memory. But now I hink I can keep up with the geeks that work here.
Then I startd a little car share app, which I will talk about some other time. Then I decided to develop dbooks a little further so I can use it in my final year.